1. Field of the Invention
The present invention is directed to a system and a method for processing used oil filters or other oil contaminated materials which will produce recyclable oil, and oil-free metal, along with energy to power a boiler or other co-generation device.
2. Prior Art
In 1997, there were approximately 417,600,000 automotive oil filters sold in the United States and only 118,000,000 were recycled. In 1998, there were 427,700,000 automotive oil filters sold in the United States and only 135,000,000 were recycled (according to the Filter Manufacturers Council). These figures are for xe2x80x9clight dutyxe2x80x9d automotive filters only and do not include the huge industrial filter market which includes heavy trucks, compressors, marine, and other filter users. In the past, used oil filters have often been buried in landfills. The U.S. Environmental Protection Agency has determined that the waste oil leakage from these used oil filters will contaminate the soil, and eventually penetrate into the water table endangering precious water supplies. Guidelines were established by the E.P.A. to eliminate the disposal of used oil filters in landfills, and many states have adopted these guidelines as state standards.
Used oil filters (automotive and industrial) contain a tremendous amount of energy and natural resources that in the past have been wasted. The vast majority of these filters consist of a steel jacket, paper or plastic filter media, and up to 25% (by weight) used oil. Crushing the filters reduces the oil content down to approximately 8%-12% (by weight). While recycling of steel is well known, it can not be accomplished effectively with oil remaining. Crushing the filters removes some of the oil for recycling, however the steel from the canister, which is covered with oil, is virtually worthless unless the residual 8%-12% of the oil is removed. Additionally, there is also approximately 10%-15% of the filter weight remaining as paper filter media. This paper (or plastic in some cases) represents a tremendous energy source with a BTU value ranging from 8,500-19,000 BTU/pound.
The used oil filter collection industry, because of the volume being generated, has begun crushing and compacting the filters into large blocks or billets. There are several prior art patents covering various devices of this type. The present invention will process all types of used oil filters and oil contaminated wastes, including, uncrushed filters, crushed filters, small compacted billets of filters (10#-35#), very large compacted billets (35#-200#), and even larger compacted billets or blocks of used oil filters. The system will also process many types of absorbents such as oily rags, oil booms, oil boom pads, oil dry granules, and the like.
The existing art either ignores the problem of oil on the steel by attempting to warm the canisters up to where there is only about 3% oil left on the steel; and these systems do not use the paper and plastic as a heat source for other devices.
There is an urgent need for a system and a method that will remove all of the waste oil from the steel so that it can be sold at normal scrap metal prices. There is also a need for a system to salvage an additional 5%-10% of the residue oil left after crushing.
There is also a need for a material recovery system and a method to utilize the heating value of the paper or plastic filter media.
There is also a need for a material recovery system and a method to be able to perform all of these things in volume, and economically, so that there is an incentive to recycle these products rather than dispose of them improperly.
Some of the existing art forms use added water in the process which generates a new water pollutant that must be treated with expensive chemicals or otherwise. These known processes are very expensive to build and to operate and produce very small quantities of finished product.
For example, Gardner (U.S. Pat. No. 5,401,293) recycles oil from filters, recondenses hydrocarbon condensate, separates the water, runs the water through an acid scrubber, and crushes filters on a press.
Barber (U.S. Pat. No. 5,135,176) discloses a batch oil filter recycler where shredded filters are stored in baskets and moved in a thermal unit by a crane. The thermal unit has a higher temperature upper chamber that receives gaseous emissions from the lower chamber.
The goal of the present invention is to provide a material recovery system and method that will enable large or small companies to process large or small quantities of used oil filters or other oil contaminated wastes at a low initial investment, and produce oil free steel, recyclable oil, and energy to power a boiler or other co-generation devices.
The present invention will cost very little to operate because the fuel source is the same waste oil that is xe2x80x9chot drainedxe2x80x9d from the system at the beginning of the cycle. Accordingly, the system is nearly self-sustaining.
A further object and purpose of the present invention is to provide a process and system to process used oil filters resulting in an extremely clean stack emission.
The present invention will accept any form of used oil filters or oil contaminated waste into alloy baskets which are placed inside of the processor which then elevates the temperature using xe2x80x9chot drain oilxe2x80x9d generated by the system as the fuel for the process. The temperature is elevated in three or four stages then control cooled in a final stage.
The present invention provides a material recovery system and a process for treating used oil filters or other oil contaminated materials. Initially, used oil filters may be crushed and then compacted into billets or blocks of filters. The billets or blocks are placed in alloy or hi-temperature wire mesh baskets. In one preferred embodiment, the wire baskets are, in turn, loaded on supports which extend from a rail car. The rail car includes a plurality of wheels which ride on a series of rails. Accordingly, the rail car is permitted to move between a loading and unloading position and a position within the furnace.
The furnace includes a pair of opposed walls, a top, one closed end, a sloping floor and an open end with the rails extending through the open end. The furnace includes a plurality of burners which extend through the opposed walls and supply heat to the furnace.
A secondary chamber is above and in fluid communication with the furnace.
The rail car has open sides and includes a car bottom with a plurality of slots. In an area surrounding each slot, the car bottom slopes toward the slot. Accordingly, any oil draining and falling from the crushed filters, through the wire baskets and onto the car bottom will drain toward and through the slots. Thereafter, the oil will move by gravity down the sloped floor of the furnace to a catch basin where it moves by gravity to a storage tank.
One end of the rail car terminates in a door which is substantially perpendicular to the bottom of the rail car. When the rail car has been moved into the furnace, the door will form an exterior wall of the furnace and close the open end of the furnace. Accordingly, a seal is created between the upstanding wall and the opening in the furnace. The rail car may be moved on the tracks by a motor or an engine.
In an alternate preferred embodiment, the wire baskets with filters are loaded through open doors of the furnace. The doors move on tracks by a roller guide assembly. Each door seals with the furnace with a triple seal arrangement to make an air-tight seal.
The material recovery process of the present invention utilizes multiple stages or steps to accomplish the desired results. After the crushed oil filters have been loaded into baskets and then sealed inside the furnace, the furnace will be heated to a first, initial stage with temperature range of from 250xc2x0 to 600xc2x0 F. During this stage, oil trapped in the filters becomes more fluid and will flow out of the filters through the wire baskets, through the car bottom and then to the bottom of the furnace where the floor is sloped.
Thereafter, the temperature will be elevated in a second stage to a second temperature range of between 400xc2x0 to 800xc2x0 F. for a second time period of from two to four hours. During this stage, the remaining free oil drains out of the oil filters. The oil will gradually stop running out of the furnace and any remaining oil within the furnace will begin to gasify. Some of these gases will proceed in gas form to the secondary chamber above the furnace.
Thereafter, the furnace is further heated to an elevated temperature in a third stage having a third temperature range of between 600xc2x0 to 1200xc2x0 F. for a time period of two to four hours. During this third stage, the filter media begins to reduce since the combustion in the furnace is sub-stoichiometric. The plastic will gasify and tend to burn as fuel in the secondary chamber and the paper will begin to form carbon black.
An optional fourth stage may be employed having a fourth temperature range of between 800xc2x0 to 1400xc2x0 F. for a period of approximately four hours.